Mechanical belt fasteners are widely employed in a variety of belt conveying applications for splicing ends of conveyor belts together. One use of such belt fasteners is to splice conveyor belts for agricultural equipment such as round hay balers and net wrap hay balers. There are hinged fastener systems that have fasteners with upper and lower plates joined by arcuate loops. The plates have apertures therein with respective apertures in the upper and lower plates being aligned so that fastener members, e.g. rivets, staples, can be installed through the apertures and the belt for clamping the plates on the corresponding belt upper and lower surfaces. With the hinged fastener so attached, the loops project beyond the belt end for cooperating with the loops of similar fasteners attached on another belt end to form a passageway through the mating loops for receiving a hinge pin therethrough thereby hingedly connecting the belt ends together.
Although the rivet belt fastener of this invention may be made in various sizes and used in various applications, it is particularly useful for agricultural equipment such as hay balers where the splices are made with small belt fasteners. Small size belt fasteners are used to pass around small diameter pulleys e.g. 3 to 3.5 inches in diameter. Currently, one of the more widely used baler belt fasteners is secured with staples rather than rivets to secure the belt fasteners to the belt. A particular problem with these splices is the abusive operating conditions encountered and hence the need for a strong, long lasting splice, which preferably can be easily applied by the farm worker in the field when making repairs or new splices. The staple fastener tools currently in use to secure the staples into the belt are rather expensive and unwieldy for the farmer; and hence there is a need for a less expensive and simpler applicator tool for easy field installation of the belt fastener splice. Thus, there is a need for a new and inexpensive applicator tool for field installation of these small belt fasteners.
During operation of the spliced conveyor belts, the fasteners are subject to loads such as due to tension forces which, if sufficiently high, can cause the belt fasteners to fail. The strength required from a fastener to avoid such failures varies to a large extent based on the application involved and thus the belt utilized. Accordingly, with light and medium duty applications such as with conveyors for food and agricultural products, fasteners having strength ratings lower than that used in more heavy-duty applications such as in underground mines and aggregate plants, can be employed. Regardless, it is desirable to have the fastener provide the greatest strength possible for the particular conveyor application with which it is to be utilized without over design thereof such as by having extra large or thick plates and greater numbers of rivets, as this could unnecessarily drive up the costs associated therewith.
In addition to keeping the costs of the fastener material down, production costs also have to be controlled so as to provide lowest cost belt fastener possible to the end user without sacrificing performance. The production costs can get to be too expensive depending on how the fasteners are made, such as if they are each individually formed as by a forging process, see, e.g., U.S. Pat. No. 5,553,359 to Herold.
In the '359 patent, the individual belt fasteners are connected in a strip by a welded wire and attached to an end of a conveyor belt by a pair of solid rivets or pins that are staked at their ends by pointed punch tools to create enlarged rivet heads. The applicator tool of Herold has to form enlarged heads on both ends of a solid pin and the applicator tool used is both expensive and fairly difficult to use in the field. One problem with this solid rivet fastener is that the enlarged heads project beyond the plane of the fastener plates associated therewith. These projecting heads are subject to frictional forces by engagement with pulleys and belt cleaners and conveyed products and thus tend to abrade and wear away over time. This wearing away of the rivet heads accordingly reduces the strength of the fastener and can lead to premature failure thereof. A further problem relates to use in conveying agricultural products, and more particularly, wrapped bales of hay such as with netting material. In this instance, it is especially important for the fastener to have a smooth, low profile with no projecting portions that could catch or snag on the net wrapping about the bales. As is apparent, the projecting rivet pin ends of the '359 patent would not be desirable for this reason. Accordingly, a hinged rivet fastener with better formed rivet heads would be desirable.
The installation of riveted belt fasteners can be done with application tools such the MSRT and SRTA tools provided by applicants' assignee herein which are adapted to drive rivet and nail assemblies, such as disclosed in U.S. Pat. No. 3,990,343, through conveyor belts so as to upset the hollow end of the rivet attached to the nail for riveting the fasteners to the belt end. The tool employs a structural steel channel body mounting hardened bushings raised over the upper surface thereof for receiving the nails of the rivet and nail assemblies when driven. The hollow ends of the rivets are upset and spread outwardly by the enlarged head of the nail and in adjacent annular trough anvil surfaces of the bushings. The bushings also provide positioning for the fasteners by fitting the countersunk rivet apertures in the lower plate of each fastener thereover. Each of the hardened bushings adds significant expense to the tool, e.g. the hardened bushings may represent approximately 35 to 40 percent of the total cost for the tool making the tool expensive for farmers to use on a sporadic basis in the field. Accordingly, a belt fastening system, and more specifically an application tool, that is less expensive would be desirable.